Heretofore, a high aromatic oil (aromatic oil) has been favorably used as a softening agent for a rubber composition and an extender oil for a synthetic rubber in the rubber compositions for tires and other region from a viewpoint of provision of high loss characteristic (high hysteresis loss characteristic), affinity with rubber and the like.
Recently, it is started to use process oils in which extraction quantity with DMSO is less than 3% by mass, which are called as Treated Distilled Aromatic Extracts (T-DAE), Mild Extracted Solvates (MES) and the like obtained by treating the high aromatic oil made from petroleum as a starting material (e.g. see JP-A-11-302459, page 2).
However, rubber compositions using an alternate oil such as T-DAE, MES or the like are low in the fracture properties and wear resistance as compared with the case using the conventional high aromatic oil, and also the temperature dependence of viscoelastic characteristics in the rubber composition tends to shift toward a low temperature side because the softening point and viscosity of the rubber itself are low. Therefore, they have a problem of causing inconvenience that the wet skid property and steering stability of the tire lower. Also, it is considered to improve the fracture properties and the wear resistance by blending with an acrylonitrile-butadiene-styrene copolymer. In this case, however, there is a problem that the deterioration of low heat buildup becomes large if it is intended to control the lowering of modulus of elasticity.